#33 ArsenicArsenic is a chemical element with symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but only the gray form, which has a metallic appearance, is important to industry. Atomic mass:74.9216 amu Melting point:817.0 C (1090.15 K, 1502.6 F) Boiling point:613.0 C (886.15 K, 1135.4 F) Density:293 K: 5.72 g/cm3 |